Control means for the throttle valves of internal-combustion engines



Feb. 12, 1952 w A. MCDONALD 2,585,814

CONTROL MEANS FOR THE THROTTLE VALVES OF INTERNAL-COMBUSTION ENGINESFiled March 25, 1948 Patented Feb. 12, 1952 UNITED STATS CONTROL MEANSFOR THE THROTTLE VALVES OF INTERNAL-COMBUSTION ENGINES 3 Claims. 1

This invention relates to automatic control means for the throttlevalves of internal cornbustion engines, and has for its general objectto provide automatic means to regulate the opening of engine throttlevalves so that more fuel will not be supplied to an engine at any giventime than the engine can consume.

As is well known, the rate of acceleration of any internal combustionengine is limited and decreases with increase in the load imposed uponthe engine. Consequently, if the throttle valve of an internalcombustion engine is opened more or suddenly an amount such that morefuel is admitted to the engine than the rate of acceleration of theengine will enable the engine immediately to consume, there will resultmore or less choking of the engine and Waste of fuel with dilution ofthe engine lubricant and accompanying bnormal wear of the engine ingeneral. Accordingly, it is these disadvantages which the presentinvention is primarily designed to avoid.

In accordance with the present invention, the negative pressure whichexists in the intake conduit of an internal combustion engine when theengine is running, and which increases and decreases with increase anddecrease in the speed of the engine, is utilized to govern operation ofthe present throttle valve control means and also as a power source foractuating the latter. In

this connection, a special and important object of the present inventionis to provide a. throttle valve control means which operates in responseto decrease in the negative pressure in the intake conduit of an engineto effect closing and to restrict opening of the engine throttle valveand upon increase in negative pressure in said conduit to efiect openingand to retard closing of said valve, whereby the supply of fuel to theengine will be regulated in accordance with the capacity of the engineto consume the same and more fuel will not, at any time, be admittedtothe engine than the engine immediately can consume.

Another special and important object of the present invention is toprovide an engine throttle valve control means which does not act eitherto retard the rate of acceleration or to limit the speed of an engine.

If the throttle valve of an internal combustion engine suddenly isclosed, the negative pressure in the intake conduit of the enginesuddenly will increase to a greater or lesser extent, depending upon thespeed of the engine, and cause the engine to consume an excessive amountof lubricant with many attendant disadvantages. Accordingly, anotherspecial and important object of the present invention is to provide anengine throttle valve control means which is efiective to prevent suddenclosing of the throttle valve so as to avoid sudden increase in thenegative pressure in the intake conduit of the engine. 7

Another special and important object of the present invention is toprovide a throttle valve control means which is operable to accomplishthe purposes stated and which is of simple, practical, inexpensiveconstruction, readily capable of incorporation in conventional types ofthrottle valve actuating means, readily adjustable to adapt it best toserve its purposes in any particular installation of the same, and whichis thoroughly reliable and highly efiicient in operation.

With the foregoing and other objects in view, which will become morefully apparent as the nature of the invention is better understood, thesame consists in an engine throttle valve control means embodying thenovel features of construction combination and arrangement of parts asare illustrated by way of example in the accompanying drawings and aswill be hereinafter more fully described and claimed.

In the accompanying drawings:

Fig. 1 is a somewhat diagrammatic view, partly in elevation and partlyin section, of a throttle valve control means constructed in accordancewith one practical embodiment of the invention; and

Fig. 2 is a view similar to Fig. 1 illustrating an alternativeembodiment of the invention; and

Figs. 3 and 4 are detail views illustrating other alternativeembodiments of the invention.

Referring to the drawings in detail, A designates in each of Figs. 1 and2 a portion of the fuel supply conduit of an internal combustion engine;B designates a throttle valve of the butterfly type for regulating flowof fuel through said conduit to the engine; {J designates an acceleratorpedal; D designates generally a connection between said acceleratorpedal and said throttle valve whereby depression of said pedal isefiective to open said throttle valve, and E designates a spring which.is operable through said connection D to raise the accelerator pedal Cupon release of foot pressure upon the same and to close said throttlevalve.

11. According to each of the diiierent illustrated embodiments of theinvention the con" nection D between the accelerator pedal C and thethrottle valve B includes a pair of rods 5:) and I l and an expansibleand contraotable charcber structure F interposed between and connectingsaid rods, whereby the effective length oi said connection D isincreased with expansion and is decreased with contraction of saidchamber structure.

Referring now particularly to the Fig. 1 embodiment of the invention, itwill be observed that the connection D is of a type such that. upondepression of the accelerator pedal C, a pushing force is exertedthrough the rods It and II to open the throttle valve B. Also it will beobserved that the expansible and contractable chamber structure Fcomprises a housing I2 having a chamber I3 therein, and a flexiblediaphragm I4 which cooperates with said housing to close said chamber,the latter being expansible and contractable by outward and inwardmovement, respectively, of said diaphragm relative to said housing.

The rod I is interposed between the accelerator pedal C and housing I2and is suitably connected firmly to the latter. On the other hand, therod II is interposed between the diaphragm I4 and a lever arm I5 on theshaft of the throttle valve B and is suitably connected at its ends tosaid diaphragm and said lever arm. In this connection and as shown, thediaphragm I4 is located at the side of the chamber I3 remote from thethrottle valve B so that if the housing I2 is held stationary and saiddiaphragm is moved inwardly relative to said chamber, opening movementis imparted to the throttle valve B, while if said diaphragm is movedoutwardly relative to said chamber, closing movement is imparted to saidthrottle valve.

Appropriately, the rod Il may extend slidably through an opening IS inthe housing I2 and through the chamber l3 to the diaphragm M and anysuitable means I! may be provided to seal said opening I6. Or, ifdesired, said rod Il may be extended around the housing I2 to thediaphragm I4. In any event, a flexible tube I8 connects the conduit Awith the chamber I3 whereby said chamber is subjected to the samenegative pressure as exists in said conduit when the engine is running.Moreover, a contractile spring I9 is interposed between and connected atits ends to the rod II and the housing I2 so as to tend constantly tomove the diaphragm I4 outwardly relative to said housing and thus eiiectclosing movement of the throttle valve B if the housing I2 is heldstationary.

Appropriately the spring I9 may surround and may be fastened to the rodII by a collar 28 which is adjustable along said rod, whereby thestrength of said spring may be adjusted.

At idling or low engine speed and with the accelerator pedal C fullyretracted, the housing I2 is stationary, the chamber I3 is subjected tolow negative pressure tending to move the diaphragm I4 inwardly relativeto said chamber and to open the throttle valve B, and the spring I9 isin tension and tending to move the diaphragm M outwardly relative to thechamber I3 and to close said throttle valve, the strength of said springI9 being such that it balances the low negative pressure force actinginwardly upon said diaphragm and holds the diaphragm in an intermediateposition. Accordingly, while sudden depression of the accelerator pedalwill result in movement of the rod I0 and the housing I2 to ward thethrottle valve B, a commensurate amount of opening movement of saidthrottle valve will not be efiected for the reason that, immediatelysaid throttle valve is partly opened, the negative pressure in theconduit A and the chamber I3 will diminish and the tensioned spring I9therefore will be permitted to act to move the diaphragm I4 outwardlyrelative to said chamber l3, thus reducing the effective length of theconnection D and limiting the amount of opening movement of the throttlevalve. In this connection, the strength of the spring I9 is such as tocontinue to act in the manner stated, even upon full depression of theaccelerator pedal, until acceleration of the engine results in progressive increase in the negative pressure in the conduit A and thechamber I3, whereupon said spring is overcome by the higher negativepressure acting inwardly upon the diaphragm l4 and the rod II is shiftedrelative to the housing I2 to progressively open the throttle valve A toadmit more fuel to the engine. The strength of the spring I9 is such, ofcourse, as to insure admission of fuel to the engine in accordance withits capacity, as determined by its rate of acceleration, to consume thesame. Accordingly, it is apparent that more fuel will not be supplied tothe engine at any given time than the engine can consume, and that theamount of fuel supplied to the engine will be in accordance with itsrate of acceleration or, in other words, will automatically increasewith increase in the speed of the engine until the negative pressure inthe conduit A and the chamber I3 becomes so high as to move thediaphragm l4 to its limit of inward movement relative to the chamber I3,which occurs at high speed of the engine.

If, during medium or higher speed of the engine, the accelerator pedal Cshould suddenly be released, closing movement of the throttle valve Bwill result in increase in the negative pressure in the conduit A andthe chamber I3 with the result that the diaphragm I4 will be drawninwardly relative to the chamber I3, thus retarding closing movement ofthe throttle valve and preventing any sudden drop in negative pressurein the conduit A with consequent avoidance of the disadvantages of anysuch sudden drop in pressure.

Referring now particularly to the Fig. 2 embodiment of the invention, itwill be observed that the connection D is of a type such that, upondepression of the accelerator pedal C, a pulling force is exertedthrough the rods It and II to open the throttle valve B. It will furtherbe observed thatthe expansible and contractible chamber structure I issubstantially the same as the Fig. 1 expansible and contractible chamberstructure, but is reversed as compared. with the Fig. 1 chamberstructure; 1. e., the diaphragm I4 is located at the side of saidstructure nearer the throttle valve B. In the Fig. 2 construction, acompression spring l9 corresponding to the tension spring IQ of the Fig.1 form of the invention, is interposed between the expansible andcontractible chamber housing I2 and a stop collar 29 on the rod II andtends constantly to move the diaphragm I4"outwardly relative to saidhousing I2 and to effect closing of the throttle valve B. It will thusbe apparent that the Fig. 2 structure has the same mode of operation asthe Fig. 1 structure and that it amounts in substance merely to areversal of the Fig. 1 structure for use in any instance where theconnection D is pulled rather than pushed to open the throttle valve B.

Fig. 3 of the drawings illustrates that a bellows 2| may be used in lieuof a flexible diaphragm in the expansible and contractible chamberstructure F. Otherwise the Fig. 3 form of the invention is generally thesame, both structurally and in mode of operation, as the Fig. 1 form ofthe invention. Obviously, the expansible and contractible chamberstructure of Fig. 3 might readily be reversed in accordance with theFig. 2 teaching to adapt the same for use in any instance where theconnection D is pulled rather than pushed to open the throttle valve B.

Fig. 4 of the drawings illustrates that a cylinder 2 and a piston Id maybe used in lieu of the housing 12 and the flexible diaphragm I4 of theFig. 1 embodiment of the invention to form the expansible andcontractible chamber structure F. Otherwise, the Fig. 4 form of theinvention is generally the same, both structurally and in mode ofoperation, as the Fig. 1 form of the invention. Obviously, the Fig. 4expansible and. contractible chamber structure might also readily bereversed in accordance with the Fig. 2 teaching to adapt the same foruse in any instance where the connection D is pulled rather than pushedto open the throttle valve B.

According to each ofthe different forms of the invention the rod Hi maybe threaded or otherwise adjustabl connected to the housing of theexpansible and contractible chamber structure F to facilitateinstallation of the control means.

From the foregoing description considered in connection with theaccompanying drawings, it is believed that the construction and mode ofoperation of the present automatic throttle control means will beclearly understood and its advantages appreciated. It is desired topoint out, however, that while only certain specific structuralembodiments of the invention have been illustrated and described, thesame is readily capable of specifically different structural embodimentswithin its spirit and scope as defined in the appended claims.

I claim:

1. In an internal combustion engine, a fuel supply conduit, a throttlevalve for controlling supply of fuel through said conduit to the engine,spring means for closing said valve, manually operable means for openingsaid valve comprising an accelerator pedal and a connection between saidpedal and said valve including a pair of rods one connected to saidpedal and the other to said valve, a housing connected to and movablewith said first mentioned rod and having a chamber therein, a flexiblediaphragm connected to and movable with said second mentioned rod andconstituting a wall of said chamber movable inwardly and outwardly withrespect to the latter, a connection between said conduit and saidchamber whereby the latter is subjected to the same negative pressure asthe former, a spring disposed exteriorly of said chamber and interposedbetween said housing and said second mentioned rod and effective to movesaid flexible diaphragm outwardly relative to said chamber and to effectclosing movement of said valve when said conduit and said chamber aresubjected to a predetermined low pressure, said spring being disposed insurrounding relationship to said second mentioned rod and beingefiective to prevent inward movement of said flexible diaphragm relativeto said chamber and consequent opening movement of said valve when saidconduit and said chamber are subjected to a predetermined highernegative pressure, and means comprising a collar on said secondmentioned rod adjustable along the latter to adjust the strength of saidspring.

2. In an internal combustion engine, a fuel supply conduit, a throttlevalve for controlling supply of fuel through said conduit to the engine,spring means for closing said valve, manually operable means for openingsaid valve comprising an accelerator pedal and a connection between saidpedal and said valve including a pair of rods one connected to saidpedal and the other to said valve, a housing connected to and movablewith one of said rods and having a chamber therein, a flexible diaphragmconnected to and movable with the other of said rods and constituting awall of said chamber, a connection between said conduit and said chamberwhereby the latter is subjected to the same negative pressure as theformer, a collar mounted on said second mentioned rod for adjustmenttherealong, means for securing said collar to said rod in difierentpositions of adjustment therealong, and a spring connected between saidhousing and said collar and of a strength to move said housing and saiddiaphragm relative to each other to effect closing movement of saidvalve when said conduit and said chamber are subjected to apredetermined low negative pressure, said spring being of insuflicientstrength to prevent relative movement between said diaphragm and saidhousing and consequent opening movement of said valve when said conduitand said chamber are subjected to a predetermined higher negativepressure.

3. In an internal combustion engine, a fuel supply conduit, a throttlevalve for controlling supply of fuel through said conduit to the engine,spring means for closing said valve, manually operable means for openingsaid valve comprising an accelerator pedal and a connection between saidpedal and said valve including a pair of rods one connected to saidpedal and the other to said valve, a housing connected to and movablewith said first mentioned rod and havin a chamber therein, a flexiblediaphragm connected to and movable with said second mentioned rod andconstituting a wall of said chamber, a connection between said conduitand said chamber whereby the latter is subjected to the same negativepressure as the former, a collar mounted on said second mentioned rodfor adjustment therealong, means for securing said collar to said rod indifferent positions of adjustment therealong, and a spring connectedbetween said housing and said collar and of a strength to move saiddiaphragm and said housing relative to each other to effect closingmovement of said valve when said conduit and said chamber are subjectedto a predetermined low negative pressure, said spring being ofinsufiicient strength to prevent relative movement between saiddiaphragm and said housing and consequent movement of said valve whensaid conduit and said chamber are subjected to a predetermined highernegative pressure.

WARD A. MoDONALD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,094,167 Riotte Apr. 21, 19142,374,411 Conner Apr. 24, 1945 FOREIGN PATENTS Number Country Date751,217 France Aug. 29, 1933

